1. Field of the Invention
This invention relates to the preparation of alkyl thiosemicarbazides by reaction of hydrazine with a dithiocarbamate.
2. Description of the Prior Art
Alkyl thiosemicarbozides are intermediates of the formula RNHC (S) NHNH.sub.2 with R preferably being lower alkyl of from 1 to 4 carbon atoms.
U.S. Pat. No. 4,132,736 to G. Cramm et al. indicates that alkyl thiosemicarbazides can be formed if a hydrazinium salt of the corresponding N-alkyl dithiocarbamic acid is heated in a solvent in the presence of sulfur, optionally in the presence of hydrazine hydrate, under conditions which pull off hydrogen sulfide and ammonia from the reaction environment.
More recently, U.S. Pat. No. 4,237,066 to D. B. Barton described a procedure for forming alkyl thiosemicarbazides by steam distilling water off from an aqueous solution containing hydrazine and an N-lower alkyldithiocarbamic acid quaternary ammonium salt thereby effecting pyrolysis while distilling off water, alkyl amine and hydrogen sulfide, and cooling the distillant to form crystals of the desired alkyl thiosemicarbazide.